how long should it take to train my pup to sit?

[binka_nugget]

It sounds like she knows what "sit" means, but chooses not to obey unless she knows there's food for her. This is how I teach sit in my class (for treat users):

-say sit while slowly putting the treat directly over the dog's head. The dog should sit automatically
-praise and reward with a treat every single time
-once the dog catches on, you can say sit without luring and work in the hand signal
-after a few days when you start to notice your dog getting it, you can slowly take away the treats.. but don't stop cold turkey. Praise is given every single time. Treats are given randomly.. the 3rd time, 5th time, 2nd time, 4th time, etc. They'll continue to work hard for you because they know the treat could come the next time! Just to give you an idea.. here's an example of the same method:

Person A gets paid the same every paycheque. It never changes. Person B also gets the occasional bonus for a job well done. Who will be more inclined to work harder every single day?

[timlewis]

what is NILIF and how did u do it n 3 days?

[BC_MoM]

what is NILIF

NILIF is Nothing In Life Is Free. The following link is a site that describes it well.
http://www.k9deb.com/nilif.htm

and how did u do it n 3 days?

It depends on the dog, and how consistent you are with your training.